Cardiovascular abnormalities in end stage renal failure: the effect of anaemia or uraemia?

Use of erythropoiesis-stimulating agents in children with chronic kidney disease: a systematic review

Background

Erythropoiesis-stimulating agents (ESAs) revolutionized the management of anaemia in chronic kidney disease (CKD) when introduced in the late 1980s. A range of ESA types, preparations and administration modalities now exist, with newer agents requiring less frequent administration. Although systematic reviews and meta-analyses have been published in adults, no systematic review has been conducted investigating ESAs in children.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for the conduct of systematic reviews was used. All available literature on outcomes relating to ESAs in children with CKD was sought. A search of the MEDLINE, CINAHL and Embase databases was conducted by two independent reviewers. Inclusion criteria were published trials in English, children with chronic and end-stage kidney disease and use of any ESA studied against any outcome measure. An assessment of risk of bias was carried out in all included randomized trials using the criteria from the Cochrane Handbook for Systematic Reviews of Interventions. Two tables were used for data extraction for randomized and observational studies. Study type, participants, inclusion criteria, case characteristics, follow-up duration, ESA type and dosage, interventions and outcomes were extracted by one author.

Results

Of 965 identified articles, 58 were included covering 54 cohorts. Six were randomized trials and 48 were observational studies. A total of 38 studies assessed the efficacy of recombinant human erythropoietin (rHuEPO), 11 of darbepoetin alpha (DA) and 3 of continuous erythropoietin receptor activator (CERA), with 6 studies appraising secondary outcome measures exclusively. Recruitment to studies was a consistent challenge. The most common adverse effect was hypertension, although confounding effects often limited direct correlation. Two large cohort studies demonstrated a greater hazard of death independently associated with high ESA dose. Secondary outcome measures included quality of life measures, growth and nutrition, exercise capacity, injection site pain, cardiovascular function, intelligent quotient, evoked potentials and platelet function.

Conclusions

All ESA preparations and modes of administration were efficacious, with evidence of harm at higher doses. Evidence supports individualizing treatments, with strong consideration given to alternate treatments in patients who appear resistant to ESA therapy. Further research should focus on randomized trials comparing the efficacy of different preparations, treatment options in apparently ESA-resistant cohorts and clarification of meaningful secondary outcomes to consolidate patient-relevant indices.

Effect of diabetes mellitus on markers of left ventricular dysfunction in chronic kidney disease

OBJECTIVES

To identify markers of left ventricular dysfunction in chronic kidney disease (CKD) and the effects of diabetes mellitus on them.

METHODS

This was a cross sectional study of 200 consecutive chronic kidney disease patients (stage III-V). Echocardiographic assessment of left ventricular function including left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), left atrial volume, grade of diastolic dysfunction, E/E', left and right ventricular myocardial performance indices (LVMPI, RVMPI) were compared between diabetic and non-diabetic CKD.

RESULTS

LVMI significantly increased with increasing stage of CKD (p < 0.001) in both diabetics (158.82 ± 48.76 gm/m2 in stage III to 201.06 ± 63.62 gm/m2 in stage V) and non-diabetics (133.14 ± 43.06 gm/m2 stage III to 196.24 ± 58.75 gm/m2 in stage V). This was significantly higher among diabetics of similar CKD stage compared to non-diabetics (p = 0.001). The LVEF worsened with increasing stage of CKD (p = 0.002) and was significantly reduced in diabetic patients (LVEF 61.96 ± 8.48 % in stage III CKD to 51.62 ± 13.45 % in stage V CKD) (p < 0.001). Diastolic dysfunction (Grades ≥2) and LA volume increased significantly with stage of CKD (p < 0.001) and was higher among diabetics (p = 0.048). Pulmonary artery systolic pressure (PASP) increased with increasing stage of CKD (p < 0.001), and was higher among diabetics (p = 0.035). E/E' worsened significantly with increasing stage of CKD and was also significantly higher in diabetics (p < 0.001). LVMPI (p < 0.001) and RVMPI (p < 0.001) were significantly reduced with worsening stage of CKD and in diabetics.

CONCLUSION

Advancing CKD stage was linearly associated with progressive left ventricular dysfunction which was significantly greater in diabetics.

Towards cardiovascular risks in children with chronic kidney disease: a prospective cohort study

Background: Children with chronic kidney disease (CKD) are at substantially high risk of morbidity and mortality from cardiovascular disease (CVD). Although this issue has been extensively studied in adults, little is known whether similar associations exist in the paediatric population. We therefore aimed to evaluate the cardiac structure and function in children with CKD, and investigate the factors that contribute to the development of CVD. Methods: A prospective cohort was established following 40 children with CKD treated in the nephrology unit at a high-volume, tertiary, teaching hospital and compared to age- and gender-matched controls of the same number.  We reviewed the patients’ medical records, assessed growth parameters, measured blood pressure, took blood samples, and performed echocardiography. Results: More than half of the CKD patients are hypertensive (N = 22; 55%) and were found to have a higher proportion of increased left ventricular mass index (LVMI) (75.5%; P = 0.001). In contrast, we did not find any significant association between CKD and both valvular calcification & left ventricular (LV) fractional shortening (FS) in children (P = 0.314). Furthermore, high LVMI is found to be correlated well with the following: anaemia, hypertension, CKD duration > one year, hyperparathyroidism, estimated glomerular filtration rate (eGFR) < 15ml/minute/1.73 m2 and death (P < 0.05). Conclusions: Despite the fact that LV systolic function is preserved and valvular calcification is usually absent, left ventricular hypertrophy (LVH) is common in children with CKD. Hypertension, anaemia, hyperparathyroidism, as well as the severity and duration of renal impairment, are amongst the additional risk factors that predispose to LVH. We contribute this study to the growing information of the review articles regarding the association between CKD and CVD in paediatrics.

Evaluation of T-wave alternans in pediatric patients with chronic renal failure

INTRODUCTION

Microvolt T-wave alternans (TWA) is known to be useful in prediction of ischemia and sudden death in high-risk populations and there are no studies in children with chronic renal failure (CRF). Cardiac problems seem to be responsible for an important part of death in children and young adults with CRF. The aim of this study is to evaluate Holter microvolts TWA measurements in children with CRF comparing to the control group.

METHODS

This prospective study included 40 patients with CRF and 48 healthy controls. The history, echocardiography and microvolt TWA values based on 24-hour ECG recordings of the patients were evaluated. Analysis of microvolt TWA was considered on the basis of three leads (V5, V1 and AVF).

RESULTS

Compared with the controls, the mean systolic and diastolic blood pressure values and average heart rates were significantly higher in the children with CRF (p = 0.001 and p = 0.026, respectively). Also, the values of left ventricular internal dimensions at end diastole and end-diastolic volume were significantly higher in CRF group (p = 0.01 and p = 0.049, respectively) and couplet ventricular extrasystole was detected in 2 patients with CRF. Consequently, all TWA values in three leads were increased in CRF group than the control group but the only increase in V5 lead was statistically significant (p = 0.028).

CONCLUSIONS

This study has demonstrated that microvolt TWA values increased in pediatric patients with CRF. TWA might be used for early risk assessment in pediatric patients with CRF in the future.

Comparison of recombinant human erythropoietin and darbepoetin alpha in children

BACKGROUND

The aim was to compare the clinical efficacy of recombinant human erythropoietin (rHuEPO) and darbepoetin alpha (DA) in the treatment of anemia in children with chronic kidney disease (CKD).

METHOD

Thirty-four (13 female, 21 male) CKD patients were enrolled in the study. Mean age was 11.42 ± 4.05 years. Nine patients were on hemodialysis, 18 were on peritoneal dialysis and seven patients were in CKD stage 4.

RESULTS

Seventeen patients received rHuEPO and the remaining 17 patients received DA. Hemoglobin (Hb) was not significantly different between the two groups during monthly follow up and at the end of 6 months (P > 0.05), but there was a significant increase within each group at the end of 6 months (P = 0.01 for rHuEPO; P = 0.02 for DA). Hb was not different between the patients on and not on dialysis in both groups at the end of the study (P > 0.05). The efficacy of the s.c. and i.v. routes was similar within each group (P > 0.05). Systolic hypertension was observed in only one patient in the DA group, no other adverse effect was observed in either groups.

CONCLUSION

DA is a reasonable alternative to rHuEPO in the treatment of anemia in pediatric CKD patients, due to its clinical efficacy, convenience of use, patient compliance and tolerability.

Hemoglobin target in chronic kidney disease: a pediatric perspective

Erythropoietin has transformed the treatment of the anemia of chronic kidney disease (CKD) by preventing the need for blood transfusions and improving the quality of life in all patients, including children. Anemia in children, in the age group 1-19 years, may be defined as hemoglobin (Hgb) levels < 12.1-13.5 g/dl for boys and < 11.4-11.5 g/dl for girls, based on the National Health and Nutrition Examination Survey (NHANES) norms. The prevalence of anemia in children ranges from 31.2% in stage 1 CKD to 93.3% in stages 4 and 5 CKD. The recent publication of trials evaluating the optimal hemoglobin level in adult CKD patients has generated considerable uncertainty about the target Hgb level in children with CKD. It is unclear whether generalizing of results from these trials in adults to children is appropriate. Adequately powered, randomized, controlled studies have not been conducted on children, and none to our knowledge are currently planned. The Food and Drug Administration (FDA) offers scant guidance on the Hgb target level for children, other than implying that it should be no different from that for adults. The purpose of this editorial is to critically scrutinize whether there is a benefit to the normalization of anemia in children with CKD and whether adoption of the results from adult studies is appropriate.

An echocardiographic assessment of cardiac functions and structure in children on dialysis

BACKGROUND

Cardiovascular complications are the most important cause of mortality in end stage renal disease. The aim of this study is to evaluate systolic and diastolic functions of children with chronic renal disease.

METHODS

Twenty-five children on renal replacement therapy (16 on peritoneal dialysis, 9 on hemodialysis), 10 children in chronic renal insufficiency group, and 27 healthy subjects were examined by echocardiography.

RESULTS

No significant difference was observed in systolic functions between patients and controls. Left ventricular mass index was significantly higher in hemodialysis and peritoneal dialysis patients when compared with controls, where no significant difference was determined between chronic renal insufficiency group and controls. Although left ventricular mass index was tended to be higher in hemodialysis than peritoneal dialysis group, this was not significant. Peak late diastolic flow velocity (A) was significantly higher in dialysis groups when compared to controls. E/A ratios were significantly lower in dialysis groups than controls.

CONCLUSION

The finding that the diastolic functions were impaired in both children on peritoneal dialysis and hemodialysis suggests that peritoneal dialysis is not superior to hemodialysis for preserving diastolic cardiac functions. Further studies with larger patient groups are needed to show long-term effects of peritoneal dialysis and hemodialysis on cardiac functions.

Anemia in children with chronic kidney disease

Anemia is a common feature of chronic kidney disease, but the management of anemia in children is complex. Erythropoietin and supplemental iron are used to maintain hemoglobin levels. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) clinical practice guidelines for the management of anemia specifically in children were recently published. Pediatric nephrologists are encouraged to use current clinical practice guidelines and best evidence in conjunction with their clinical experience to optimally manage patients with anemia.

Cardiovascular complications of pediatric chronic kidney disease

Cardiovascular disease (CVD) mortality is a leading cause of death in adult chronic kidney disease (CKD), with exceptionally high rates in young adults, according to the Task Force on Cardiovascular Disease. Recent data indicate that cardiovascular complications are already present in children with CKD. This review summarizes the current literature on cardiac risk factors, mortality and morbidity in children with CKD.

Anemia in children with chronic kidney disease

Anemia in children with chronic kidney disease (CKD) is common secondary to inadequate erythropoietin production, iron deficiency, blood loss, inflammation, secondary hyperparathyroidism, uremic toxins, and nutritional deficiencies. Anemia has a variety of deleterious consequences, including associations with increased mortality and left ventricular hypertrophy. Recombinant human erythropoietin is effective in treating anemia in children with CKD, and recent studies show that darbepoetin alpha is an attractive alternative because it requires less frequent injections. Iron deficiency is a major cause of anemia that is resistant to erythropoietin or darbepoetin alpha. Although oral iron is effective in some patients, many children, especially those receiving hemodialysis, require intravenous iron to replenish their iron stores. Both acute dosing and chronic dosing of intravenous iron are effective in pediatric patients.

Prevalence of anemia in erythropoietin-treated pediatric as compared to adult chronic dialysis patients

BACKGROUND

Recent guidelines recommend a target hemoglobin range of 11 to 12 g/dL in pediatric and adult dialysis patients. We compared anemia prevalence in United States Medicare pediatric and adult dialysis patients.

METHODS

Prevalent hemodialysis patients (0 to 19 years, pediatric: N= 1692; adult: N= 352,291) and peritoneal dialysis patients (pediatric: N= 597; adult: N= 39,136) treated with recombinant human erythropoietin (rHuEPO) from 1996 to 2000 were selected. Mean annual hemoglobin values were calculated by modality, age, sex, and race.

RESULTS

Among hemodialysis patients, mean annual hemoglobin values less than 11 g/dL were present in pediatric and adult patients during 54.1% versus 39.8% patient years, respectively (P < 0.0001); for peritoneal dialysis patients, 69.5% versus 55.1% (P < 0.0001). Mean hemoglobin values increased over time and were 11.2, 11.5, 10.8, and 11.2 g/dL for pediatric and adult hemodialysis and peritoneal dialysis patients, respectively, in 2000. Pediatric hemodialysis patients received intravenous iron less frequently than adults (66.3% vs. 82.5% patient years; P < 0.0001).

CONCLUSION

Hemoglobin values in rHuEPO-treated pediatric dialysis patients lagged behind those of adult patients, with pediatric patients achieving target hemoglobin values only a minority of the time (45.9% and 30.5% patient years, respectively, for hemodialysis and peritoneal dialysis). Trends show recent improvement in anemia treatment of children on dialysis. Still, further attention to and analysis of rHuEPO and iron therapy in pediatric dialysis patients is warranted.

Echocardiographic changes and risk factors for left ventricular hypertrophy in children and adolescents after renal transplantation

Long-term consequences of cardiac alteration in children with chronic renal failure and after renal transplantation are largely unknown. In chronic uremia, cardiomyopathy manifests itself as systolic dysfunction, concentric left ventricular hypertrophy (LVH) or left ventricular dilatation. The correction of uremic state by renal transplantation leads to normalization of left ventricular contractility, regression of LVH and improvement of cavity volume and so dialysis patients with uremic cardiomyopathy would benefit from renal transplantation. We studied 73 patients, aged 17 yr or less, who underwent renal transplantation in our center. This cross-sectional study was performed 4.6 yr (median) after transplantation. Of the total, 48 were males and 25 were females. Transthoracic echocardiographic examination was performed for all cases. The effects of clinical, demographic, biochemical and therapeutic data on echocardiographic parameters were assessed. Multivariate analysis was used to assess the relation between the risk factors and the left ventricular muscle mass index. The most common echocardiographic abnormalities were the LVH (47.9%), left atrial enlargement (31.5%) and left ventricular dilatation and systolic dysfunction (13.7% for each). The pretransplant dialysis, arteriovenous fistula, acute rejection, cumulative steroid dose per square meter surface area, post-transplant hypertension, anemia and graft dysfunction were significant risk factors for LVH by univariate analysis. The significant factors by multivariate analysis were pretransplant dialysis, post-transplant hypertension and anemia. From this study we may conclude that LVH is a common problem among renal transplant children and adolescents. Early transplantation, control of hypertension and correction of anemia may be beneficial regarding left ventricular function and structure.

Homocysteine and left ventricular hypertrophy in children with chronic renal failure

Hyperhomocysteinemia is recognized as an independent risk factor for cardiovascular disease, especially atherosclerosis, in adult patients with chronic renal failure (CRF). However, there is little information about the relationship between plasma homocysteine levels and left ventricular hypertrophy. The aim of this study was to determine plasma homocysteine levels and risk factors for left ventricular hypertrophy and to investigate the relationship between plasma homocysteine concentration and left ventricular mass index (LVMI) in children with CRF. The homocysteine level was measured by high-performance liquid chromatography and LVMI was calculated using echocardiographic findings in 27 children with CRF and 16 healthy controls. The mean LVMI and mean plasma homocysteine concentration in the CRF group, especially in patients with end-stage renal disease, were statistically higher than the control group ( P<0.05). There was no correlation between LVMI and plasma homocysteine concentration. There was a positive correlation between plasma homocysteine concentration and serum creatinine level. There was a positive correlation of LVMI with creatinine and blood pressures (systolic, diastolic, and mean arterial pressure). There was a negative correlation of LVMI with hemoglobin level in multiple linear regression analysis. In our view homocysteine does not have a direct effect on left ventricular structure and left ventricular hypertrophy is the end organ damage associated with hypertension, anemia, and CRF. More prospective studies are needed to better clarify the inter-relationships of plasma homocysteine level and left ventricular structure in children with CRF.

Unexpectedly high prevalence of posttransplant anemia in pediatric and young adult renal transplant recipients

BACKGROUND

Although posttransplant anemia (PTA) is recognized as a common problem in adult renal transplant recipients, few pediatric studies have been published.

METHODS

In this retrospective cohort study of 162 pediatric renal transplant recipients treated at Stanford University, the authors sought to determine the prevalence, severity, and the predictive factors of PTA. Anemia was defined as a hematocrit (HCT) level greater than 2 SD below published means for age or as erythropoietin dependency to maintain a normal HCT.

RESULTS

Sixty-seven percent of pediatric renal transplant recipients were anemic at the time of transplantation. The prevalence of anemia increased to 84.3% in the first month posttransplant. From 6 months to 60 months posttransplant, the prevalence of anemia remained high at 64.2% to 82.2%. Only 4 patients (2.5%) were never anemic. Iron depletion was detected in 19 of 26 and 23 of 23 anemic patients 12 and 60 months posttransplant, respectively. Serum erythropoietin levels were low relative to hematocrit levels in 38 of 56 anemic patients. Logistic regression at 3 months posttransplant showed that discharge hematocrit level (P < 0.0001), calcium (P = 0.0004), and cyclosporine dose (P = 0.0002) correlated with anemia. Creatinine clearance (P = 0.002) and white blood cell count (P = 0.004) correlated with anemia at 12 months posttransplant, but only creatinine clearance (P = 0.011) correlated with anemia 60 months posttransplant.

CONCLUSION

Nearly all pediatric renal transplant recipients experience PTA. However, few children less than 2 years of age were anemic during the first year posttransplant. Antirejection therapy, bone disease, iron depletion, and creatinine clearance appear to play pivotal roles in the development of PTA in children.

Risk factors for cardiovascular disease in children on maintenance dialysis

Cardiovascular disease mortality is high in children on maintenance dialysis, accounting for about 25% of patient deaths. Cardiovascular-related mortality rates for children on dialysis are higher than for children with successful kidney transplants. Data on the long-term consequences of risk factors for cardiovascular disease are lacking for pediatric end-stage renal disease patients. This article reviews pediatric data pertaining to the following risk factors: anemia, hypertension, hyperlipidemia, left ventricular hypertrophy, abnormal calcium-phosphorus metabolism, and hyperhomocysteinemia. The potential relationship of end-stage renal disease to the etiology of several functional disorders of the cardiovascular system is discussed. Clinical studies are needed to assess the prevalence of cardiovascular disease and of cardiovascular disease risk factors in the pediatric end-stage renal disease population. Possible preventive and therapeutic guidelines need to be developed for at-risk children on maintenance dialysis.

An altered repolarizing potassium current in rat cardiac myocytes after subtotal nephrectomy

Renal failure in humans is associated with electrocardiographic changes including altered QT interval dispersion, which suggests that cardiac myocyte repolarization is abnormal and which appears to correlate with cardiac prognosis. In this study, cardiac myocyte repolarizing currents have been studied in isolated cells from rats 8 wk after subtotal nephrectomy (SNx), using sham-operated animals as controls. In addition, monophasic cardiac action potentials were recorded from the epicardial surface of the left ventricle (LV) apex, LV base, and the right ventricle of isolated perfused hearts paced at 320/min. SNx was associated with cardiac hypertrophy and histologic evidence of myocardial fibrosis, but SNx rats were not hypertensive. Repolarizing K(+) currents were measured using whole-cell patch-clamp, and 4-aminopyridine (4-AP)-sensitive transient outward (I(to)) and 4-AP-insensitive sustained outward (I(so)) components were quantified. After SNx, I(to) was increased by two to threefold at voltages from -30 to +60 mV and showed increased heterogeneity. For example, at 0 mV voltage clamp pulse, the median I(to) was increased from 3.23 pA/pF in control myocytes (interquartile range 3.20 pA/pF, n = 24) to 5.86 pA/pF in SNx myocytes (interquartile range 7.32 pA/pF, n = 21, P: < 0.005). The kinetics of inactivation of I(to) were altered after SNx with slowing both of the onset and the recovery from inactivation. The mean time constant of inactivation at +30 mV after SNx was 14.2 +/- 1.6 ms (n = 20) compared with control values of 9.8 +/- 0.6 ms (n = 23, P: < 0.05). Neither I(so) nor inward rectifier K(+) currents were altered after SNx. The action potential duration (APD(50)) at the left ventricular base was approximately 20% shorter (P: < 0.02) in hearts from SNx rats compared with controls. 4-AP (2 mM) prolonged the APD(50) in all regions in hearts from both SNx and control rats and abolished the APD(50) shortening in SNx. These results indicate that abnormalities of the cardiac transient outward K(+) current contribute to alterations in the cardiac action potential in renal failure and warrant further investigation because they may contribute to altered repolarization and arrythmogenesis.

Left ventricular abnormalities in children, adolescents and young adults with renal disease

The cardiac abnormalities that complicate chronic renal failure and renal replacement therapy are not well characterized in young people. These abnormalities are becoming more important because successful renal transplantation has resulted in children with end-stage renal failure living longer. Echocardiographic abnormalities of cardiac function and structure were studied in children and young adults (< 27 years old) with chronic renal failure (CRF, N = 32), end-stage renal failure treated with chronic peritoneal dialysis (CPD, N = 10) or renal transplantation (N = 30) or controls (N = 60). Left ventricular mass indexed for height (LVM/Ht and LVM/Ht2.7) and body surface area (LVM/SA), fractional shortening, measurement of left ventricular diastolic function (peak E and A wave velocities and the EA ratio) and structural (such as valvular) abnormalities were determined by echocardiography. The median (and range) of LVM/Ht in the groups were control 51.8 (23.1 to 119.8), CRF 60.2 (22.2 to 135.8), CPD 80.2 (14.5 to 100.9) and transplant group 97.8 (51.2 to 182.1) g/m. The increases in LVM/Ht, LVM/Ht2.7 and LVM/SA in the transplant group were significant (P < 0.01). The CRF group had significantly increased LVM/Ht2.7 and LVM/SA (P < 0.01). Systolic function was not significantly different between the groups. A significant correlation between creatinine and LVM indexed for height was found in the CRF group. Systolic or diastolic blood pressure could not be correlated with LVM indices in the transplant group. Changes in diastolic function were found (increased peak A wave velocity and decreased E/A ratios in the CRF and CPD groups, and increased peak E wave velocity in the transplant group). The study demonstrated that left ventricular hypertrophy is a frequent and often severe finding in children with chronic renal failure and those treated with renal replacement therapy. Factors other than hypertension and anaemia are important, and evidence was found for a link between serum creatinine and increased left ventricular mass prior to end-stage renal failure.